Effective of acetylsalicylic acid, indomethacin, phenylbutazone, paracetamol, ibuprofen and naproxen on canine gastric mucosa: a histological and ultrastructural study.

The effect of various non-steroidal analgesic drugs on gastric mucosal cells was studied in 48 dogs with 2 other dogs as control. Each drug was instilled into the stomach of 8 anaesthetised dogs through a gastrostomy. Gastric biopsies, obtained at 0, 1, 2 and 3 hours after administration of the drug, were subjected to histological and electron microscopical examination. Histological analysis did not show any significant changes in gastric mucosal cells in any of the drug-related groups as compared to controls. Electron microscopy, however, showed significant changes in the gastric mucous cells and parietal cells of all test groups, as compared to controls. Ultrastructural abnormalities in mucous cells included dilation of cisternae of endoplasmic reticulum, loss of granules and microvilli, and thickening of the mucous layer and were most pronounced with acetylsalicylic acid, moderate with phenylbutazone, indomethacin and naproxen, but mild with paracetamol and ibuprofen. Parietal cell changes consisting of reduction in the concentration of tubulovesicles, which canaliculi, were found to be severe with indomethacin and phenylbutazone, moderate with paracetamol and naproxen, but only minimal with acetylsalicylic acid and ibuprofen.